Smartphones and other electronic devices have evolved enormously over the past few years, and so too have their batteries. Lithium batteries dominate the market, and are by far the most frequently used batteries for most electronic devices. That said, researchers have spent a long time looking for an alternative to lithium, and for good reason.
Everything is becoming wireless, integrated, mobile and portable - devices still need electricity. Most batteries are powered by lithium. Lithium-ion batteries are commonly used in smartphones, tablets, headphones, clocks and many other objects. But fears are growing that the ever increasing demand for batteries will ultimately sap important reserves like cobalt or lithium. As a result, research is underway to address the threat of a lithium shortage before it hits.
Sodium batteries - too hot to handle
Researchers are systematically testing new material bases for a battery. They are especially interested in elements from the first group of the periodic table. These can emit electrons - which is the basic principle behind all current battery power. Additionally, atoms must be as light as possible in order to store more energy than mass.
One promising candidate is sodium. This substance has properties similar to lithium, which led to the first sodium-sulfur batteries being created some 50 years ago. The practical issue is, however, that for good performance a sodium battery needs to be operated at a minimum of about 300 degrees Celsius (That's around 570 degrees Fahrenheit). This is necessary to avoid damage to the anodes (you can find a complete overview at Battery University). Another downside is that liquid sodium is highly flammable and very difficult to dispose of safely.
The development of sodium batteries that are safe to operate at room temperature began a long time ago. Since these are being developed with the same design as lithium-ion batteries, it's still missing the target. A suitably high-performance cathode still hasn't been found for the larger ions.
Phosphorus is potentially a solution for this part of this battery. However, prototype batteries need a long time to charge - seven or more hours for a smartphone-sized battery - otherwise, only a fraction of the battery's capacity is filled. It's unlikely that this sort of battery will be ready for the market any time soon.
Instead of sodium, some researchers have billed magnesium as the basic material for upcoming super-batteries. Magnesium can emit two electrons at a time, and in its purest form, can serve as an anode. However, the design of these batteries must be chemically redeveloped.
As it stands today, the difference to lithium batteries is still too stark. The potential is nevertheless huge. A magnesium-sulfur battery would, at least theoretically, contain four times the energy density of today's lithium-ion cells. At the moment, this would only sustain a few charging cycles - the system is still too fragile. A breakthrough here does appear to be possible, but not necessarily in the near future.
Aluminum-ion batteries create other issues. Their energy density of 40 watts per kilogram is comparable to old lead-acid batteries. They are too small for modern smartphones, tablets and other devices. Researchers are nevertheless still on the case, as aluminum-ion batteries can withstand very high charging currents and an extremely large number of charging cycles. Achieving full charge in one minute is conceivable for a smartphone. Aluminum is also cheap, as is a possible graphite cathode. That said, it will be a while before this idea is ready to be manufactured for the industry.
Lithium will be sticking around for a while
The bottom line is that it will take a long time before lithium-ion batteries face any serious competition. All of the current alternatives require a lot more development. This research is also very expensive, while using lithium remains simple and cheap. In addition, the intention is not to push lithium-ion out of the market, but to find a better or cheaper option which is as flexible and safe as current technology. What that battery will look like remains an exciting question.